Field of the Invention
The present invention relates generally to a printer capable of printing a single sheet as well as at least one continuous strip of paper.
A printer of the type mentioned is disclosed by WO 91/13765 A1. In that patent, a matrix printing head with its needle mouthpiece pointing upward is arranged underneath a printing substrate plane, and the printer housing can be folded up in the plane of the printing substrate. A paper supply roll and a wind-up roll and a cutting device for a continuous paper strip are accommodated so that they are easily accessible in the upper part of the printer housing, which makes the threading of the start of a new continuous paper strip considerably easier. The arrangement has the further advantage that a single sheet and the continuous paper strip(s) can be fed to the plane of the printing substrate and led away from the latter over completely separate paths, so that a continuous paper strip which is always located in the printer and a single sheet can overlap. In order for it to be printed, a single sheet is pushed between the printing head and the endless paper strip on a level, horizontally aligned feed table. Following printing, the single sheet is transported out of the printer by pairs of transport rollers which are intended only for single-sheet transport. The continuous paper strip is then located directly in front of the printing head again and can be printed.
The advantages of the known arrangement cannot be transferred to a printer having an inkjet printing head since, as is known, such printing heads cannot print upward from below. Simply exchanging the printing head and printing support does not solve the problem, since a continuous paper web which is always located in the printer would shield a single sheet from the printing head. On the other hand, the handling of a printer substrate which is common in office printers, in which a continuous paper strip is pulled back out of the printing area before a single sheet is threaded, is impractical in the case of a cashdesk printer. Here, it is necessary to change continually between document and counterfoil printing, and too much time would be needed to pull back and re-feed the continuous paper strip which is normally used for counterfoil printing. In the case of a journal recording, in which a continuous paper strip is unwound from a supply roll and, behind the printing station, is wound up onto a wind-up roll, such a method could not be used in any case.
Therefore, there is a need for a printer having a printing station for printing a single sheet and at least one continuous paper strip on a single printing substrate plane, which is suitable for the use of an inkjet printing head.